using System;

public class Program

{

    public static void Main()

    {

        double testeDouble_min = 12.3456;

        double testeDouble_max = 12.8456;

        double emptyDouble;

        int i01_min = Convert.ToInt32(testeDouble_min); //12

        int i01_max = Convert.ToInt32(testeDouble_max); //13

        //var erro = Convert.ToInt32(emptyDouble); //error  

        Console.WriteLine(i01_min);

        Console.WriteLine(i01_max);

​

        int i02_min = (int)testeDouble_min; //12

        int i02_max = (int)testeDouble_max; //12

        //var erro = (int)emptyDouble; //error  

        Console.WriteLine(i02_min);

        Console.WriteLine(i02_max);

​

        var styles = System.Globalization.NumberStyles.Integer | System.Globalization.NumberStyles.AllowDecimalPoint;

        var provider = new System.Globalization.CultureInfo("en-US");

        bool success = int.TryParse(testeDouble_min.ToString(), styles, provider, out int i03_min); //0

​

        _ = int.TryParse(testeDouble_max.ToString(),  out int i03_max); //0 because it has decimal place, if it didn't have ok

        Console.WriteLine(i03_min);

        Console.WriteLine(i03_max);

        int i04_min = (int)Math.Round(testeDouble_min, MidpointRounding.AwayFromZero); //12

        int i04_max = (int)Math.Round(testeDouble_max, MidpointRounding.AwayFromZero); //13

        //int i04_empty = (int)Math.Round(emptyDouble, MidpointRounding.AwayFromZero); //error

        Console.WriteLine(i04_min);

        Console.WriteLine(i04_max);     

    }

}